Coffee machine



FIG. 1 is a front, right side perspective view of a coffee machine showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a rear view thereof; and,

FIG. 6 is a top view thereof.

The broken lines show portions of the coffee machine, which form no part of the claimed design. 

CLAIM The ornamental design for a coffee machine, as shown and described. 